JP2012232580A - Laminated polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polyester film in which adhesion and antistatic performances that are conventionally considered as incompatible are compatible at high levels.SOLUTION: The laminated polyester film includes a coating layer having a thickness of 0.01-0.07 μm on at least one surface of the polyester film. The coating layer is formed from a coating liquid containing an acrylic resin having hydrophilic groups derived from a reactive emulsifier in the molecule, an oxazoline compound, and a compound having quaternary ammonium.

Description

  The present invention relates to a polyester film having an excellent antistatic property and a coating layer having excellent adhesion to various topcoats.

  Biaxially stretched polyester films are excellent in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, etc., and are used in various fields.

  In particular, in recent years, it is used as a surface protective film for optical members such as polarizing plates, retardation plates and laminates conforming thereto, and substrates for optical films such as lens sheets used for liquid crystal displays such as computers and televisions. Is increasing.

  In such applications, various top coats such as paints, inks, pressure-sensitive adhesives, and adhesives are processed on polyester films. However, since the biaxially stretched polyester film has a highly crystallized surface, it has a drawback that it is inferior in adhesion to these various topcoats.

  As one method for solving such problems related to adhesion, there is a method in which various resins are applied to the surface of a polyester film to provide an application layer having easy adhesion performance.

  On the other hand, the polyester film has a characteristic that it is easily charged due to static electricity as a problem common to plastic films. For this reason, problems such as poor running performance of processed films or processed products, attracting ambient dust, etc., and when optical films are used, multiple films stick to each other due to static electricity, causing the films to bend and causing unevenness in image quality. Problems arise. As for suppression of charging of the polyester film, there is a method of providing a coating layer having antistatic performance on the film.

  However, conventional antistatic coating layers are inferior in adhesion, and none of the adhesion and antistatic properties are compatible at a sufficient level.

JP-A-5-1164 Japanese Patent Laid-Open No. 8-143691

  The present invention has been made in view of the above-mentioned problems, and provides a laminated polyester film that has been considered to be incompatible with the related art, and has a high level of both adhesion and antistatic performance. There is.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be easily solved by adopting a specific configuration, and the present invention has been completed.

  That is, the gist of the present invention is that the polyester film has an application layer having a thickness of 0.01 to 0.07 μm on at least one surface, and the application layer has a hydrophilic group derived from the reactive emulsifier in the molecule. The present invention resides in a laminated polyester film formed from a coating solution containing a resin, an oxazoline compound, and a compound having a quaternary ammonium group.

  According to the present invention, it is possible to provide a laminated polyester film that has been considered to be incompatible with each other and that has both adhesion and antistatic performance at a high level, and the industrial value of the present invention is high.

  The base film of the laminated polyester film of the present invention is made of polyester. Such polyesters include dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 4,4′-diphenyldicarboxylic acid, 1,4-cyclohexyldicarboxylic acid or esters thereof. It is a polyester produced by melt polycondensation with glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol. Polyesters composed of these acid components and glycol components can be produced by arbitrarily using a commonly used method.

  For example, a transesterification reaction between a lower alkyl ester of an aromatic dicarboxylic acid and a glycol, or a direct esterification of an aromatic dicarboxylic acid and a glycol, to form a substantially bisglycol of an aromatic dicarboxylic acid A method is employed in which an ester or a low polymer thereof is formed and then polycondensed by heating under reduced pressure. Depending on the purpose, an aliphatic dicarboxylic acid may be copolymerized.

  Typical examples of the polyester of the present invention include polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and the like. It may be a polymerized polyester and may contain other components and additives as necessary.

  The polyester film in the present invention can contain particles for the purpose of ensuring the film runnability and preventing scratches. Examples of such particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, calcium phosphate, kaolin, talc, aluminum oxide, titanium oxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and molybdenum sulfide. Further, organic particles such as crosslinked polymer particles and calcium oxalate, and precipitated particles during the polyester production process can be used.

The particle size and content of the particles to be used are selected according to the use and purpose of the film, but the average particle size (d50)
Usually, it is 0.01 μm to 3 μm, preferably 0.02 μm to 2.5 μm, and more preferably 0.03 μm to 2 μm. If the average particle size exceeds 3.0 μm, the surface roughness of the film may become too rough, or the particles may easily fall off from the film surface. When the average particle size is less than 0.01 μm, the surface roughness is too small and sufficient slipperiness may not be obtained.

About particle | grain content, it is 0.0003 to 1.0 weight% normally with respect to polyester, Preferably it is the range of 0.0005 to 0.5 weight%. When the particle content is less than 0.0003% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 1.0% by weight, the transparency of the film is poor. It may be enough. In addition, when it is particularly desired to ensure the transparency and smoothness of the film, the film may be substantially free of particles.
Further, various stabilizers, lubricants, antistatic agents and the like can be appropriately added to the film.

  In addition, it is preferable that the haze of the laminated polyester film obtained by this invention is 10% or less. More preferably, it is 5% or less, More preferably, it is 3% or less. If it is larger than this range, it may be difficult to use in optical film applications.

  As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, a sheet obtained by melt extrusion is first stretched 2 to 6 times at 70 to 145 ° C. by a roll stretching method to obtain a uniaxially stretched polyester film, and then perpendicular to the previous stretching direction in the tenter. A film is obtained by extending | stretching 2 to 6 times at 80-160 degreeC to the direction, and also heat-processing at 150-250 degreeC for 1 to 600 seconds. Further, at this time, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the transverse direction in the heat treatment zone and / or the cooling zone at the heat treatment outlet is preferable.

  The polyester film in the present invention has a single layer or multilayer structure. In the case of a multilayer structure, the surface layer and the inner layer, or both the surface layer and each layer can be made of different polyesters depending on the purpose.

  The coating layer of the present invention can be provided by either a so-called off-line coating in which a coating layer is provided later on the formed film or a so-called in-line coating in which a coating layer is provided during film formation. However, it is preferably provided by in-line coating, particularly a coating stretching method in which stretching is performed after coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film. Specifically, it is a method of coating at any stage from melt extrusion of polyester to biaxial stretching and then heat setting and winding. is there. Normally, it is coated on either a substantially amorphous unstretched sheet obtained by melting and quenching, then a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction), or a biaxially stretched film before heat setting. To do. In particular, as a coating stretching method, a method of stretching in the transverse direction after coating on a uniaxially stretched film is excellent. According to such a method, since film formation and coating layer coating can be performed at the same time, there is a merit in manufacturing cost. Stabilize. Moreover, the polyester film before biaxial stretching is first covered with a resin layer constituting the coating layer, and then the base film and the coating layer are firmly adhered by stretching the film and the coating layer simultaneously. become. In addition, the biaxial stretching of the polyester film is achieved by stretching the film in the lateral direction while holding the film end with a tenter clip, so that the film is constrained in the longitudinal / lateral direction and is flat without wrinkles or the like in heat setting. High temperature can be applied while maintaining the nature. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer is improved, and the coating layer and the polyester film are firmly adhered. As the polyester film provided with the coating layer, the uniformity of the coating layer, the improvement of the film forming property, and the adhesion between the coating layer and the film often produce preferable characteristics. However, since heat resistance is required for the resin used as the coating layer, it is necessary to sufficiently study the selection of the resin to be used.

  In the case of the coating stretching method, the coating solution to be used is preferably an aqueous solution or an aqueous dispersion for safety reasons in terms of handling, working environment, but water is the main medium and does not exceed the gist of the present invention. If so, an organic solvent may be contained.

  The coating layer of the present invention is a coating layer containing a coating solution containing an acrylic resin having a hydrophilic group derived from a reactive emulsifier in the molecule, an oxazoline compound, and a compound having a quaternary ammonium group. It can be obtained by drying and curing. The coating solution may contain other components.

  When each component is not completely reacted, the resulting coating layer contains both unreacted products and reaction products of each component, and the ratio of the reaction product and unreacted product depends on the curing conditions. It can be changed as appropriate.

  As described above, in the conventional technique, adhesion and antistatic performance are not compatible at a sufficient level. The reason for this is not always clear, but it is thought that there are the following reasons.

  That is, in order to obtain sufficient antistatic performance by coating, it is necessary to increase the thickness of the coating layer in order to obtain the necessary amount of antistatic component. When the forced peeling test is performed after the top coat is processed, the coating layer itself tends to cohesive failure in addition to peeling at the interface between the coating layer and the top coat layer. Therefore, sufficient adhesion cannot be ensured. In order to prevent this cohesive failure, if the cohesive force of the coating layer itself is increased by using, for example, a crosslinking agent, the antistatic component network in the coating layer is inhibited, and the antistatic performance is reduced, or the coating layer is coated to prevent cohesive failure When the layer is thinned, the total amount of antistatic components is reduced, and the antistatic performance is lowered. In addition, when the ratio of the antistatic component to the effective component of the entire coating layer is increased instead of increasing the thickness of the coating layer, if these components have poor adhesion, the resulting coating layer also has high adhesion. I couldn't.

  In other words, in order to achieve both antistatic performance and adhesion, it was necessary to find a new combination in the selection of materials to be used and the configuration of the coating layer.

  In the present invention, the acrylic resin contained in the coating solution for forming the coating layer is composed of a polymerizable monomer having a carbon-carbon double bond, as typified by acrylic and methacrylic monomers. It is a polymer.

  Examples of the polymerizable monomer having a carbon-carbon double bond include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, and the like. Various hydroxyl group-containing monomers such as salts, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroxyfumarate, monobutylhydroxyitaconate , Various (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylimide, di Acetone acrylamide Various nitrogen-containing vinyl monomers such as N-methylolacrylamide or (meth) acrylonitrile, various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, vinyl acetate, vinyl propionate, etc. Various vinyl esters are exemplified, and in the present invention, a copolymer containing at least one of acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester is particularly preferable.

  Moreover, when polymerizing such monomers to obtain an acrylic resin, the present invention is preferably obtained in the form of an aqueous dispersion using an emulsion polymerization method in which the monomers are dispersed and polymerized in water. An emulsifier is used to disperse the monomer in water. In the present invention, it is preferable to use a nonionic or anionic reactive emulsifier. In acrylic resins obtained using other emulsifiers, the resulting coating layer often does not exhibit sufficient adhesion. The reactive emulsifier here refers to an emulsifier having a radical polymerizable double bond in the molecule and copolymerizing in the resin during the polymerization of the acrylic resin. It is particularly preferable that it is nonionic, and in that case, a hydrophilic group using an alkylene oxide is preferable. In the case of an anionic property, a sulfate group is preferable as the hydrophilic group.

  The obtained acrylic resin aqueous dispersion preferably has an average dispersed particle size in the range of 0.01 to 0.2 μm, more preferably 0.02 to 0.09 μm. When the average dispersed particle size is larger than the above range, the appearance and adhesion of the resulting coating layer tend to be inferior. Moreover, when smaller than the said range, there exists a tendency which is still inferior to adhesiveness.

  In the present invention, the compound having a quaternary ammonium group contained in a coating solution for forming a coating layer refers to a compound having a quaternized ammonium group in the molecule, and particularly a polymer compound. Is preferred. Moreover, it is preferable that it is a water-soluble compound.

  In the present invention, for example, a polymer containing as a component a monomer having a quaternary ammonium group and an unsaturated double bond can be used.

  Specific examples of such a polymer include a polymer having a constituent represented by the following formula 1 or 2 as a repeating unit. These homopolymers and copolymers, and other plural components may be copolymerized.

In the above formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is —O— or —NH—, and R ³ is —R ⁷ — or —R ⁷ —A—R ^8. - (provided that the alkylene group of ^{R 7} and ^{R 8} carbon atoms, which may be substituted is 1 to 6, a is, -O -, - NH- or -N _{(CH 3)} ^{2 +} - represents a), R ⁴ , R ⁵ , and R ⁶ are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ⁻ is a monovalent anion.

In the above formula, R ¹ and R ² are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ⁻ is a monovalent anion.

The polymer having the component represented by the above formula 1 is excellent in transparency of the resulting coating layer and is preferable. However, in the coating stretching method, heat resistance may be inferior, and when used in the coating stretching method, X ⁻ is preferably not a halogen.

  The compound represented by the above formula 2 and other compounds having a quaternary ammonium base in the polymer skeleton are excellent in heat resistance, and antistatic properties are easily obtained even in the coating stretching method.

  Moreover, in this invention, it is necessary to contain an oxazoline compound in the coating liquid for forming a coating layer.

  The oxazoline compound in the present invention refers to a compound having an oxazoline group in the molecule, and can be synthesized using a monomer containing an oxazoline group as at least one raw material monomer. Examples of such monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2- Vinyl-5,6-dihydro-4H-1, -oxazine, 4,4,6-trimethyl-2-vinyl-5,6-dihydro-4H-1,3-oxazine, 2-isopropenyl-2-oxazoline, 4,4-dimethyl-2-isopropenyl-2-oxazoline, 4-acryloyl-oxymethyl-2,4-dimethyl-2-oxazoline, 4-methacryloyl-oxymethyl-2,4-dimethyl-2-oxazoline, 4 -Methacryloyl-oxymethyl-2-phenyl-4-methyl-2-oxazoline, 2- (4-vinylphenyl) -4,4-dimethyl-2-o Oxazoline, 4-ethyl-4-hydroxymethyl-2-isopropenyl-2-oxazoline can be exemplified 4-ethyl-4-ethoxymethyl-2-isopropenyl-2-oxazoline and the like. One or more of these or other oxazoline group-containing monomers can be used.

  Moreover, in this invention, it is preferable to copolymerize the other component which does not contain an oxazoline group. Here, the other component is not particularly limited as long as it is a monomer that can be copolymerized with an oxazoline group-containing monomer. For example, a resin copolymerized with a vinyl oxazoline monomer using a monomer containing a vinyl group, such as (meth) acrylic acid esters, (meth) acrylamides, and styrene monomers, has high reactivity and is industrially obtained. Cheap.

  The coating solution may contain other cross-linking agents.

  As a ratio in the non-volatile component of the coating liquid, the ratio of the acrylic resin having a hydrophilic group derived from the reactive emulsifier in the molecule is usually 5 to 70% by weight, preferably 15 to 50% by weight, and a quaternary ammonium group. The proportion of the compound having is usually 10 to 80% by weight, preferably 20 to 70% by weight, and the proportion of the oxazoline-based crosslinking agent is usually 5 to 60% by weight, preferably 10 to 40% by weight. The coating layer eventually becomes a mixture of these components and their reactive organisms.

  The coating solution for providing the coating layer can contain components other than those described above as necessary. For example, surfactants, other binders and antistatic agents, lubricants, particles, antifoaming agents, coatability improving agents, thickeners, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like. These additives may be used alone or in combination of two or more as necessary.

  The upper limit of the thickness of the coating layer as the film thickness on the finally obtained film is 0.07 μm, preferably 0.05 μm or less. The lower limit is 0.01 μm, preferably 0.02 μm or more. When the composition of the coating layer is limited as described above and the thickness of the coating layer is within the above range, both adhesion and antistatic performance can be achieved at a high level.

The antistatic property of the coating layer is measured by the surface specific resistance of the coating layer. It can be said that the lower the surface resistivity, the better the antistatic property. If the surface resistivity is 1 × 10 ¹³ Ω or less, it can be said that there is no problem with antistatic properties, and if it is 1 × 10 ¹² Ω or less, it can be said that the antistatic properties are extremely good.

  As a method for applying the coating solution to the polyester film, for example, a coating technique as shown in “Coating system” published by Yuji Harasaki, Tsuji Shoten, published in 1979 can be used. Specifically, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roll coater, transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, calendar coater And a technique such as an extrusion coater.

  In addition, in order to improve the applicability | paintability to the film of a coating agent and adhesiveness, you may give a chemical process, a corona discharge process, a plasma process, etc. to a film before application | coating.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, the evaluation method in an Example and a comparative example is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Average particle size of particles added to the polyester film (d50)
The size of the particles was measured by a sedimentation method based on Stokes' resistance law using a Shimadzu centrifugal sedimentation type particle size distribution analyzer SA-CP3 type.

(3) Average particle diameter of coating composition The aqueous dispersion of the coating composition was diluted to an appropriate concentration, and the 50% average diameter of the number average was measured with a Nikkiso Microtrac UPA.

(4) Thickness of coating layer A film was fixed with an embedding resin, a cross section was cut with a microtome, and a sample was prepared by staining with 2% osmic acid at 60 ° C. for 2 hours. The obtained sample was observed with a transmission electron microscope (JEM2010 manufactured by JEOL Ltd.), and the thickness of the coating layer was measured. A total of 15 points on the film are measured, and an average of 9 points excluding 3 points from the larger value and 3 points from the smaller value is defined as the coating layer thickness.

(5) Antistatic property Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and measuring electrode: HP16008B, measuring the surface resistivity after conditioning the sample for 30 minutes in a measurement atmosphere at 23 ° C. and 50% RH did.

(6) Adhesiveness The active energy ray-curable resin composition as shown below was applied onto the coating layer of the sample so that the thickness after curing would be 7 μm, and the hot-air drying oven set at 80 ° C. And dried for 1 minute. Next, using a high-pressure mercury lamp with an energy of 120 W / cm, curing was performed by irradiation for about 7 seconds at an irradiation distance of 100 mm to obtain a laminated film in which an active energy ray-curable resin layer was provided on the film. The integrated light amount of the active energy ray at this time was measured using an ultraviolet integrated light amount meter UIT-250 and a light receiver UVD-C365 (manufactured by USHIO INC.), And was about 110 mJ / cm ² . The active energy ray-cured resin layer of the obtained laminated film is cross-cut so that there are 100 grids per inch, and 18 mm wide tape (Nichiban cello tape (registered trademark) CT-18) Was attached, a rapid peel test was performed, and the adhesion was evaluated based on the peeled area. The judgment criteria are as follows.
A: Number of cross-cuts = 0
○: 1 ≦ Number of cross cuts ≦ 10
Δ: 11 ≦ number of cross-cuts ≦ 20
×: 21 <Number of cross-cuts peeled ××: Whole surface peeled Cured resin composition: 80 parts by weight of KAYARAD DPHA manufactured by Nippon Kayaku, 20 parts by weight of KAYAARD R-128H manufactured by Nippon Kayaku, 5 IRGACURE651 manufactured by Ciba Specialty Chemical A composition in which a mixture by weight is diluted with toluene to a concentration of 30% by weight.

(7) Transparency According to JIS K 7136 (ISO14782), the haze of the film was measured using a turbidimeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). It can be said that the lower the haze, the better the transparency.

The polyester raw materials used in Examples and Comparative Examples are as follows.
(Polyester 1): Polyethylene terephthalate having an intrinsic viscosity of 0.66 that does not substantially contain particles (Polyester 2): containing 0.3% by weight of amorphous silica having an average particle diameter (d50) of 1.6 μm, Polyethylene terephthalate having an intrinsic viscosity of 0.65 Further, the following was used as the coating composition.
(E1): a polymer compound having a number average molecular weight of 20000, obtained by copolymerizing a structural unit of the following formula 1-1 and a structural unit of the following formula 1-2 at a weight ratio of 95/5.

(E2): a polymer compound composed of a structural unit of the following formula 2-1

(E3): a polymer compound having a structure in which a structural unit of the following formula 3-1 and an acrylate ester are copolymerized

(A1):
In the presence of alkoxy polyethylene glycol methacrylate as a reactive emulsifier, copolymerization was carried out with alkyl acrylate, alkyl methacrylate, methacrylic acid and N-methylol acrylamide as the main components, glass transition point of 50 ° C., acid value of 14 mg KOH, Acrylic resin (C1) having an average particle size of 0.05 μm: Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd.), which is a polymer type cross-linking agent having an oxazoline group branched to an acrylic resin
(C2): Becamine J-101 (made by Nippon Materials), which is methoxymethylol melamine.
(C3): Denacol EX-521 (manufactured by Nagase ChemteX) which is polyglycerol polyglycidyl ether
(F1): Silica sol aqueous dispersion having an average particle size of 0.07 μm (S1): Surfactant Surfinol 465 (manufactured by Air Products)

Comparative Example 1:
A blend of polyester 1 and polyester 2 at a weight ratio of 92/8 was used as the raw material for layer A, and polyester 1 alone was used as the raw material for layer B. To the outer layer (surface layer) and the B layer as an intermediate layer, and coextruded in a layer configuration of two types and three layers (A / B / A) using an electrostatic adhesion method. The film was cooled and solidified while being in close contact with a mirror surface cooling drum having a surface temperature of 40 to 50 ° C., and an unstretched polyethylene terephthalate film having a thickness composition ratio of A / B / A = 3/94/3 was prepared. This film was stretched 3.7 times in the longitudinal direction while passing through a heating roll group at 85 ° C. to obtain a uniaxially oriented film. Next, this film was guided to a tenter stretching machine, stretched 4.0 times in the width direction at 100 ° C., further heat treated at 230 ° C., and then subjected to a relaxation treatment of 2% in the width direction. An axially oriented polyethylene terephthalate film was obtained. The properties of this film are shown in Table 2 below.

Example 1:
A coating solution as shown in Table 1 below was applied to one side of a uniaxially oriented film obtained in the same process as Comparative Example 1. Next, the film was guided to a tenter stretching machine, and the coating composition was dried using the heat, and the film was formed on a biaxially oriented polyethylene terephthalate film having a film thickness of 100 μm by the same process as in Comparative Example 1. A laminated polyester film provided with a coating layer having a thickness shown in 1 was obtained. The properties of this film are shown in Table 2 below.
Examples 2-5, Comparative Examples 2-6:
In the same process as in Example 1, the coating solution was changed as shown in Table 1 to obtain a laminated polyester film in which a coating layer was provided on a base film having a film thickness of 100 μm. The properties of this film are shown in Table 2.

  However, the weight ratio in Table 1 represents the weight ratio of the active ingredient of each component in the coating solution.

  The film of the present invention can be suitably used as a biaxially stretched polyester film in applications requiring excellent antistatic properties and adhesion to various topcoats.

Claims (3)

The polyester film has a coating layer having a thickness of 0.01 to 0.07 μm on at least one surface of the polyester film, and the coating layer has an acrylic resin having a hydrophilic group derived from a reactive emulsifier in the molecule, an oxazoline compound, and 4 A laminated polyester film formed from a coating solution containing a compound having a quaternary ammonium group. The laminated polyester film according to claim 1, wherein the coating layer has a surface specific resistance of 1 × 10 ¹³ Ω or less. The laminated polyester film according to claim 1 or 2, wherein the film haze is 10% or less.